AutoCodes – Generic – U18C1

U18C1 Code - Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus

Quick Answer

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Suspension Control Module, Suspension Control Module harness is open or shorted, Suspension Control Module circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U18C1 indicates Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus.
Common causes: Common causes include Faulty Suspension Control Module, Suspension Control Module harness is open or shorted, Suspension Control Module circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 586

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 09, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U18C1 Description

Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. The Diagnostic Trouble Code (DTC) will set a supervised periodic message that includes the transmitter device availability that has not been received.

OBDII Code U18C1 - Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus - AutoCodes.com — U18C1 Code - Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus

What does this mean?

What are the Possible Causes of the DTC U18C1?

Faulty Suspension Control Module
Suspension Control Module harness is open or shorted
Suspension Control Module circuit poor electrical connection

How to Fix the DTC U18C1?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U18C1 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U18C1 code?

Need more information on how to fix the U18C1 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U18C1 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U18C1 Buick — Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus
U18C1 Cadillac — Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus
U18C1 Chevrolet — Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus
U18C1 GMC — Lost Communication With Suspension Control Module On Chassis Expansion CAN Bus

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U18C1 Code

1. What are common symptoms of OBDII code U18C1?

- Common symptoms include dashboard warning lights related to the suspension system, suspension issues, and possible loss of control over the vehicle's suspension settings.

2. What can cause the OBDII code U18C1 to trigger?

- This code is typically triggered when there is a communication failure between the vehicle's onboard computer and the suspension control module on the chassis expansion CAN bus.

3. How can I diagnose the U18C1 code?

- Diagnosing this code usually involves using a diagnostic scanner to retrieve the code, checking for any loose or damaged wiring connections, and testing the communication between the modules.

4. Is it safe to drive with the U18C1 code present?

- It is not recommended to drive with this code present, as it can affect the proper functioning of the suspension system and potentially compromise the vehicle's safety and handling.

5. Can a DIY enthusiast repair the U18C1 code?

- While checking for loose connections or damaged wiring can be done by an experienced DIY enthusiast, diagnosing and repairing communication issues between modules may require specialized knowledge and tools best handled by a professional mechanic.

6. How much does it typically cost to repair the U18C1 code?

- The cost of repairing this code can vary depending on the underlying cause. It may involve simple fixes like reconnecting wires or more complex repairs like module replacement, which can range from a few hundred to a few thousand dollars.

7. Can the U18C1 code be intermittent?

- Yes, this code can sometimes be intermittent, meaning the communication issue may come and go. It is important to address the problem promptly to avoid potential safety hazards.

8. What are the potential long-term effects of ignoring the U18C1 code?

- Ignoring this code can lead to ongoing suspension issues, compromised ride quality, and potential safety risks due to the loss of communication between critical vehicle systems.

9. Are there any preventative measures to avoid the U18C1 code?

- Regular maintenance checks, including inspecting wiring harnesses and connectors for signs of wear or damage, can help prevent communication failures that trigger this code.

10. Can a software update fix the U18C1 code?

- In some cases, a software update from the manufacturer may address communication issues causing the U18C1 code. It's recommended to consult with a professional mechanic or dealership to determine if a software update is available for your specific vehicle.